Residue desulfurization with catalyst whose pore volume is distributed over wide range of pore sizes



United States Patent 3,383,301 RESIDUE DESULFURIZATIUN WITH CATALYSTWHOSE FORE VOLUME IS DISTRIBUTED OVER WIDE RANGE OF PURE SIZES HaroldBeuther, Gihsonia, and Bruce K. Schmid,

McCandless Township, Allegheny County, 1321., assignors to Gulf Research& Development Company, Pittsburgh, Pa., a corporation of Delaware NoDrawing. Filed Jan. 20, 1966, Ser. No. 521,816 8 Claims. (Cl. 208-216)ABSTRACT OF THE DISCLOSURE The disclosure relates to thehydrodesulfurization of sulfur-containing petroleum oils containingresidual components and metallic contaminants employing catalystcomprising a hydrogenating component composited on an alumina base whosepore volume is distributed over a wide range of pore sizes.

This invention relates to desulfurization of petroleum oils containingresidual components and having high sulfur contents and moreparticularly to a catalytic hydrodesulfurization process for reducinghigh sulfur content petroleum oils containing residual components by theuse of catalytic compositions that are especially effective for suchpurpose.

Residual petroleum oil fractions containing relatively high proportionsof sulfur as well as high sulfur crude oils are relatively less salablethan the corresponding oils of low sulfur content. In fact, high sulfurresidual fuels may be entirely unsalable in some localities, since theycannot be used as low grade fuel in municipalities that have adoptedmaximum sulfur specifications for fuels burned in their jurisdictions.Such residual fuels may be still more difiicultly disposable when theirviscosities and/ or heavy metals content are so great as to requiredilution with the relatively large proportions of cutter stocks ofrelatively greater value.

It has been proposed to improve the salability of high sulfur content,residual-containing petroleum oils by a variety of hydrodesulfurizationprocesses. However, difficulty has been experienced in achieving aneconomically feasible catalytic hydrodesulfurization process, becausenotwithstanding that the desulfurized products may have a widermarketability, the manufacturer may be able to charge little or noadditional premium for the low sulfur desulfurized products, and sincehydrodesulfurization operating costs have tended to be relatively highin view of the previously experienced, relatively short life forcatalysts used in the hydrodesulfurization of residual-containingstocks. Short catalyst life is manifested by inability of a catalyst tomaintain a relatively high capability for desulfurizing charge stockwith increasing quantites of coke and/or metallic contaminants which actas catalyst poisons. Satisfactory catalyst life can be obtainedrelatively easily with distillate oils but is especially diificult toobtain in desulfurizing petroleum oils containing residual components,since the asphaltene or asphaltic components of an oil, which tend toform disproportionate amounts of coke, are concentrated in the residualfractions of a petroleum oil, and since a relatively high proportion ofthe metallic contaminants that normally tend to poison catalysts arecommonly found in the asphaltene components of the oil.

The present invention relates to a process for the catalytichydrodesulfurization of sulfur-containing petroleum oils containingresidual components and containing metallic contaminants in the presenceof a catalyst having an unusual tolerance for the coke and metalliccontaminants that accompany processing of residual-containing stocks,:as evidenced by a continued high level of desulfurization activity,notwithstanding a relatively heavy deposition of coke and metalcontaminants. In accordance with the process of this invention asulfur-containing petroleum oil that contains residual components andmetallic contaminants normally tending to act as catalyst poisons, iscontacted with hydrogen at hydrodesulfurization conditions in thepresence of a catalyst comprising at least one hydrogenating componentcomposited with an alumina base, said composite catalyst having not morethan 15 percent of the volume of the pores having a radius in the rangeof 0 to 300 Angstrom units in any 10 Angstrom unit incrernent of poreradius in the range of pores having a 0 to 120 Angstrom unit radius, andalso having at least about 10 percent of such pore volume in poreshaving a radius of less than 30 Angstrom units, at least 15 percent ofsuch pore volume in pores having a radius greater than 30 Angstrom unitsand less than 70 Angstrom units, and at least 30 percent of such porevolume in pores having a radius of greater than 70 Angstrom units andless than 120 Angstrom units. Catalysts of the class indicated that alsohave a surface area of at least 100 square meters per gram arepreferred. The hydrodesulfurization reactions of the present process canbe effected at a hydrogen partial pressure in the range of about 500 to4000 p.s.i.g., preferably about 1000 to 2000 p.s.i.g., a temperature,after startup, in the range of about 600 to 850 F., preferably about 650to 800 F., at a space velocity in the range of 0.1 to 10, preferablyabout 0.5 to 5, volumes of liquid per volume of catalyst per hour, usinga hydrogenzoil ratio in the range of about 1000 to 15,000, preferablyabout 5000 to 10,000 s.c.f. of hydrogen per barrel of oil. Especiallyadvantageous results are obtained by the present invention in thedesulfurization of petroleum oil stocks containing at least 2 percentsulfur and at least 10 ppm. vanadium, and when the operating conditionsof the process are so selected and maintained as to produce a constantreduction in sulfur content of about 40 to 80 percent, preferably 50 topercent.

The feed stock to the desulfurization reaction zone of the presentprocess can be any sulfur-containing petroleum stock containing residualmaterials. Since the catalysts of the class disclosed herein have anespecially high tolerance for feed stocks containing metalliccontaminants normally tending to act as catalyst poisons, the presentprocess is especially advantageous in connection with crude oilscontaining at least 10 p.p.m. vanadium and with residues containing atleast 20 ppm. vanadium. Since an important advantage achieved by thepresent invention is the maintenance of a relatively high level ofdesulfurization, notwithstanding a relatively large accumulation of cokedeposits and metallic contaminants, the invention is especially usefulin connection with crude oils containing at least 1.5 percent sulfur andwith residues containing at least 2 percent sulfur. From what has beensaid, it will be clear that the feed stock can be a whole crude.However, since the high sulfur content components of a crude oil tend tobe concentrated in the higher boiling fractions, the present processmore commonly will be applied to a bottoms fraction of a petroleum oil,i.e., one which is obtained by atmospheric distillation of a crudepetroleum oil to remove lower boiling materials such as naphtha andfurnace oil, or by vacuum distillation of an atmospheric residue toremove gas oil. Typical residues to which the present invention isapplicable will normally be substantially composed of residualhydrocarbons boiling above 900 F. and containing a substantial quantityof asphaltic materials. Thus, the charge stock can be one having aninitial or 5 percent boiling point somewhat below 900 F., provided thata substantial proportion, for example,

about 40 or 50 percent by volume, of its hydrocarbon components boilabove 900 F. A hydrocarbon stock having a 50 percent boiling point ofabout 900 F. and which contains asphaltic materials, 3 percent by weightsulfur and 15 ppm. vanadium is illustrative of such charge stock.

The hydrodesulfurization reactions effected pursuant to the process ofthis invention are carried out at a temperature that is maintained,after the relatively rapid elevation of temperature employed duringstartup, in the range of about 600 to 850 F. Hydrodesulfurization attemperatures in the range of about 650 to 800 F. are preferred, sincenotwithstanding that the same given degree of desulfurization can bemaintained at higher temperatures, relatively larger proportions ofgaseous products are produced, which products involve a disproportionateconsumption of hydrogen.

The desulfurization reactions are effected in the presence of uncombinedhydrogen partial pressures in the range of about 750 to 4000 p.s.i.g.The process of this invention is especially useful in connection withdesulfurizations in which the degree of desulfurization is maintained ata relatively high level, i.e., 40 to 80 percent, preferably 50 to 75percent, and in which hydrogen consumption is minimized. To this end weprefer to carry out the process of this invention at hydrogen partialpressures in the range of 1000 to 2500 p.s.i.g.

The desulfurization reactions of the subject process are carried out ata liquid hourly space velocity in the range of 0.1 to 10, preferablyabout 0.5 to 5 liquid volumes of oil per volume of catalyst per hour.

The hydrogen gas which is used during the hydrodesulfurization iscirculated at a rate between about 1000 and 15,000 s.c.f./bbl. of feedand preferably between about 5000 and 10,000 s c.f./bbl. The hydrogenpurity may vary from about 60 to 100 percent. If the hydrogen isrecycled, which is customary, it is desirable to provide for bleedingoff a portion of the recycle gas and to add makeup hydrogen in order tomaintain the hydrogen purity within the range specified. Satisfactoryremoval of hydrogen sulfide from the recycled gas will ordinarily beaccomplished by such bleed-off procedures. However, if desired, therecycled gas can be washed with a chemical absorbent for hydrogensulfide or otherwise treated in known manner to reduce the hydrogensulfide content thereof prior to recycling.

As indicated, the invention is especially beneficial Wherehydrodesulfurization is effected without concomitant cracking of thehydrocarbons present in the feed stock. To achieve this objective, thetemperature and space velocity are selected within the ranges specifiedthat will result in the reduction in the sulfur content of the feedstock of about 40 to 80 percent, preferably 50 to 75 percent, and sothat no more than about 1 to 5 gram moles of hydrogen will be consumedper gram atomic weight of sulfur removed from the feed stock.

As indicated, it has been found that the nature of the catalyst employedin the process is very important with respect to the results achieved.The class of catalysts useful for purposes of the present inventioncomprises those containing at least one hydrogenating componentcomposited with an alumina carrier, which composite catalyst has notmore than 15 percent of the volume of the pores having a radius of 0 to300 Angstrom units in any Angstrom unit increment of pore radius in therange of pores having a 0 to 120 Angstrom unit radius. Furthermore, thepore volume should be more or less uniformly distributed over this rangeso that at least about 10 percent of the above pore volume of the poreshaving a radius in the range of 0 to 300 Angstrom units is in poreshaving a radius of less than 30 Angstrom units, at least percent of suchpore volume is in pores having a radius of greater than Angstrom unitsand less than 70 Angstrom units, and at least 30 percent of such porevolume is in pores having a radius of greater than 70 Angstrom units andless than 120 Angstrom units.

It will be appreciated that for most porous catalyst supports, the majorportion of the pore volume will be in pores of less than 300 Angstromunits radius and that by far the major portion of the total pore volumein these relatively small pores will be found in pores having a radiusfrom 0 to 120 Angstrom units. Since the chief portion of the total porevolume of a given porous catalyst support material is normally made upof pores in the 0 to 120 Angstrom unit radius range, it is these poresthat are considered to be chiefly responsible for the behavior of agiven catalyst. Although the present invention is based on the discoveryof a correlation between the hydrodesulfurization of petroleum residuesand the distribution of the pore volume in the 0 to 120 Angstrom unitradius range, the pore volume fractions set forth herein have beenstated in terms of the volume of the pores having a radius in the 0 to300 Angstrom unit radius range, since pore volume distribution, asmeasured by conventional nitrogen adsorption-desorption techniques, isnormally reported in these terms.

For most porous catalytic supports, particularly those considered to beespecially effective in the hydrodesulfurization of distillate stocks,it has been observed that a very high concentration of the pore volumewill be concentrated in pores of about the same size, and it has beenpostulated that there is a correlation between the catalytic effect of acatalyst, the diameter or radius of the most frequently occurring poresize, and the average molecular diameter of the feed stock. While thistheory may hold true for the desulfurizing activity of catalysts withrespect to distillate feed stocks, it has now been found that contraryto supposition, what is needed for greater effectiveness in thedesulfurization of residual stocks is not a catalyst having a largeconcentration of pores of any particular size range, but rather acatalyst having a relatively uniform, wide distribution of pores overthe entire 0 to 120 Angstrom radius range.

While the mechanism by which the catalysts of this invention functionhas not been conclusively established, it is considered that theirunusual effectiveness may be due to the fact that there are sufficientlarge pores present to accommodate the preferentially adsorbed largemolecules without blocking, so that the pores in other size ranges,which would normally tend to become blocked by the coked residue oflarge molecules, remain relatively free to effect desulfurization ofsmall and intermediate sized molecules. This hypothesis is supported bythe fact that catalysts of the class disclosed herein show superioraging characteristics as compared to catalysts having a disproportionatepore volume distribution, even though the latter catalysts show higherinitial desulfurizing activity.

Thus, the class of catalysts included by the present invention comprisesthose containing at least one hydrogenating component composited with aporous alumina support, which composite catalyst has not more than 15percent of the volume of the pores having a radius in the range of 0 to300 Angstrom units in any 10 Angstrom unit increment of pore radius inthe range of pores having a 0 to 120 Angstrom unit radius, and alsohaving at least about 10 percent of such pore volume in pores having aradius of less than 30 Angstrom units, at least 15 percent of such porevolume in pores having a radius greater than 30 Angstrom units and lessthan 70 Angstrom units, and at least 30 percent of such pore volume inpores having a radius of greater than 70 Angstrom units and less than120 Angstrom units. Such catalysts also should have a surface area of atleast square meters per gram.

Catalysts of the class indicated can be obtained in any convenient way,for example by impregnation of a suitable alumina support with solutionscontaining the desired hydrogenating component or components, drying andcalcining. Suitable alumina supports, like the finished catalysts, arethose having not more than 15 percent of the volume of the pores havinga radius in the range of 0 to 300 Angstrom units in any Angstrom unitincrement of pore radius in the range of pores having a 0 to 120Angstrom unit radius, and also having at least about 10 percent of suchpore volume in pores having a radius of less than 30 Angstrom units, atleast percent of such pore volume in pores having a radius greater than30 Angstrom units and less than 70 Angstrom units, and at least 30percent of such pore volume in pores having a radius of greater than 70Angstrom units and less than 120 Angstrom units. Such supports can beobtained as articles of commerce or they can be prepared in anyconvenient manner. An example of a suitable commercial support areselected batches of Filtrol Grade 86 alumina having the indicated poreVolume distribution.

Alternatively, a support having the desired pore volume distribution canbe prepared by precipitation, at a pH in the range of about 4.5 to 6.0of aluminum hydroxide from an aqueous solution of aluminum sulfate, at atemperature in the range of about 160 to 210 F., preferably 180 to 200F., by addition of ammonia gas or ammonium hydroxide. The pH of themixture can be raised as high as 8 to minimize peptization or colloidformation. The mixture is preferably allowed to age for a period of atleast 4 to 6 hours or longer, preferably with stirring, in order tocomplete the reaction as far as possible. The elevated temperature ismaintained throughout the aging period. After aging, the precipitate isfiltered and washed free of sulfate ions and dried. The thusobtainedmixture Will comprise a crystalline alumina mixture containingprincipally boehmite and bayerite aluminas. This material is thencalcined with a suitable hot gas, such as flue gas, at a temperature inthe range of about 1000 to 1250 F. and suflicient to obtain atemperature in the solids such as to effect substantial dehydration ofthe water of constitution. The calcined product will have the pore sizedistribution characteristic of the class of supports useful for thepurposes of the present invention.

It is emphasized that the hydrogenating components need not be depositedon the support after calcination, and, if desired, can be deposited onthe dried uncalcined support, prior to calcination.

The hydrogenating component of the class of catalysts disclosed hereincan be any material or combination thereof that is effective tohydrogenate and desulfurize the charge stock under the reactionconditions utilized. For example, the hydrogenating component can be atleast one member of the group consisting of Group VI-B and Group VIIImetals in a form capable of promoting hydrogenation reactions,especially effective catalysts for the purposes of this invention arethose comprising molyb denum and at least two members of the iron groupmetals. Preferred catalysts of this class are those containing nickel,cobalt and molybdenum, but other combinations of iron group metals andmolybdenum such as iron, nickel and molybdenum and iron, nickel andmolybdenum and iron, cobalt and molybdenum, as well as combinations ofnickel and molybdenum, cobalt and molybdenum, nickel and tungsten orother Group VI-B or Group VIII metals taken singly or in combination.The hydrogenating components of the catalysts of this invention can beemployed in sulfided or unsulfided form; however, the use of catalystswhose hydrogenating component is in sulfided form is preferred.

Although the hydrogenating components indicated above can be employed inany proportions with respect to each other, especially effectivecatalysts for the purposes of this invention are those in which thehydrogenating component is selected from the group consisting ofsulfides and oxides of (a) a combination of about 2 to 25 percent,preferably 4 to 16 percent, by Weight molybdenum and at least 2 irongroup metals where the iron group metals are present in such proportionsthat the atomic ratio of each iron group metal with respect tomolybdenum is less than about 0.4, and (b) a combination of about 5 to40 percent, preferably 10 to 25 percent, by weight of nickel andtungsten where the atomic ratio of tungsten to nickel is about 1:01 to5, preferably 1:03 to 4.

When the use of a catalyst in sulfided form is desired, the catalyst canbe presulfided, after calcination, or calcination and reduction, priorto contact with the charge stock, by contact With a sulfiding mixture ofhydrogen and hydrogen sulfide, at a temperature in the range of about550 to 650 F., at atmospheric or elevated pressures. Presulfiding can beconveniently effected at the beginning of an onstream period at the sameconditions to be employed at the start of such period. The exactproportions of hydrogen and hydrogen sulfide are not critical, andmixtures containing low or high proportions of hydrogen sulfide can beused. Relatively low proportions are preferred for economic reasons.When the unused hydrogen and hydrogen sulfide utilized in thepresulfiding operation is recycled through the catalyst bed, any waterformed during presulfiding is preferably removed prior to recyclingthrough the catalyst bed. It will be understood that elemental sulfur orsulfur compounds, e.g., mercaptans, that are capable of yieldinghydrogen sulfide at the sulfiding conditions, can be used in lieu ofhydrogen sulfide.

Although presulfiding of the catalyst is preferred, it is emphasizedthat this is not essential as the catalyst will normally become sulfidedin a very short time by contact, at the process conditions disclosedherein, with the high sulfur content feed stocks to be used.

EXAMPLE 1 In a specific embodiment, a catalyst representative of theclass disclosed herein was prepared by deposition of the desiredhydrogenating components on a commercial, calcined alu-rnina base havinga density of 39.0 pounds per cubic foot, a surface area of 299.6 squaremeters per gram, a pore volume of 0.79 milliliter per gram and anaverage pore radius of 79.1 Angstrom units. A typical sample of thecalcined base had a pore volume distribution over the range of poreshaving a radius from 0 to 300 Angstrom units as follows:

Pore radius, A.: Pore volume, percent The hydrogenating componentscomprised a combination of 8 percent molybdenum, 1 percent cobalt and0.5 percent nickel. The atomic ratios of these metals were as follows:0.2 Co and 0.1 NizMo. A catalyst of equivalent makeup and properties issuitably prepared by impregnating an alumina base having the pore volumedistribution indicated with a solution of ammonium paramolybdate in anaqueous ammoniacal solution. The amount of ammonia used in the solutionwas sufficient to yield ammonium monomolybdate. The catalyst base isimpregnated with the ammonium molybdate solution using the incipientwetness technique. Following the initial impregnation, the material isdried for 24 hours at a temperature above that required to evaporatewater of impregnation.

After drying, the nickel and cobalt metals are deposited on themolybdenum-alumina from a water solution of the metal nitrates. Thethus-impregnated base is then dried as described and calcined at 900 to1000 F. in an oxygen-containing gas, whereby the hydrogenating metalcomponents are converted to the oxide form.

The finished catalyst employed in the runs described below had a totalpore volume of 0.46 ml./g., a surface area of 165.8 m. /g., and anaverage pore radius of 74.5 Angstrom units and a pore volumedistribution, over the range of pores having a radius from to 300Angstrom units, as follows:

Pore radius, A.: Pore volume, percent The above-described catalyst wasused in the catalytic hydrodesulfurization of a Kuwait crude oilcontaining approximately 2.5 percent sulfur and approximately 30 p.p.m.vanadium. The sulfur content of the residual fuel oil component of thecrude (650 F. plus residue) was 4.0 percent. The conditions employed inthe reaction were 2400 p.s.i.g. total reaction pressure (2000 p.s.i.g.hydrogen partial pressure) and a space velocity of 3.28 liquid volumesof oil per volume of catalyst, while maintaining a hydrogen to oil ratioof 5000 s.c.f./bbl. In this operation, the initial stabilized reactiontemperature, following initial rapid temperature increase duringstartup, was 726 F. after four days of operation. At that time thesulfur content of the residual fuel oil component of the product (650 F.plus residue) was approximately 1.16 percent. The reaction was allowedto continue with temperature elevation as required to maintain thesulfur content of the residual fuel oil component of the crude oil feedstock below 1.3 percent sulfur. After 56 /2 days of continuousoperation, the sulfur content of the residual fuel oil component of theproduct had not exceeded 1.3 percent and the temperature of the reactionhad not exceeded 760 F.

By way of contrast, in a similar aging run carried out at 2400 p.s.i.g.total reactor pressure (2000 p.s.i.g. hydrogen partial pressure), aspace velocity of 3.0 liquid volumes of oil per volume of catalyst perhour, while maintaining a hydrogen to oil ratio of 5000 s.c.f./bbl. oil,using a catalyst containing the same quantities of nickel, cobalt andmolybdenum deposited on a commercial alumina carrier, where the finishedcatalyst had 28.4 percent of the pore volume of pores having a radius of0 to 300 Angstrom units in pores having a radius of 30-40 Angstrom unitsand 28.8 percent of such pore volume in pores having a radius of -30Angstrom units, but only 7.1 percent of such pore volume in pores havinga radius of 50 to 60 Angstrom units, 2.4 percent in the 60 to 70Angstrom unit range, 0.5 percent in the range of 70 to 80 Angstromunits, 0.4 percent in the range of 80 to 90 Angstrom units, 0.2 percentin the range of 90 to 100 Angstrom units, and which was known to be veryeffective for desulfurization of petroleum distillate fractions, thepercent sulfur in the residual fuel oil component of the product was 1.1percent at 704 F. after two days. After 20 days the temperature had beenraised to 769 F.,

and the percent sulfur in the residual fuel oil component of the productwas 1.52 percent.

Similarly, still another aging run was carried out with the same Kuwaitcrude oil charge stock at a total reaction pressure of 2300 p.s.i.g.(2000 p.s.i.g. hydrogen partial pressure), a 3.1 liquid hourly spacevelocity, using a hydrogen to oil ratio of 9000 s.c.f./bbl. whereinthere was employed a catalyst containing the same portions of nickel,cobalt and molybdenum as in the above-indicated catalyst, deposited on acommercial alumina having 20.2 percent of the pore volume of the poreshaving a radius of 0 to 300 Angstrom units in pores having a radius of10-20 Angstrom units and 25.2 percent of such pore volume in poreshaving a radius of 20-30 units, but only 6.9 percent in the range of 50to 60 Angstrom units, 3.2 percent in the range of 60 to Angstrom units,1.9 percent in the range of 70 to Angstrom units, 1.5 percent in therange of 80 to Angstrom units, and 1.0 percent in the range of 90 toAngstrom units. Although this catalyst had been found highly effectivefor desulfurization of petroleum distillates, the sulfur content of theresidual fuel oil component of the product increased from about 1.16percent at two days and a temperature of 735 F. to 1.64 percent after 20days, in spite of an increase in temperature to 765 F. during that time.

EXAMPLE 2 In another specific embodiment, the charge stock of Example 1is hydrodesulfurized at the conditions of Example 1 with a catalyst of 6percent nickel and 19 percent tungsten, in sulfided form, deposited onthe alumina of Example 1.

The unusual coaetion during hydrodesulfurization, between catalysts ofthe class disclosed herein and highsulfur petroleum oils containingresidual components, has been demonstrated by comparative experiments inwhich separate samples of a Kuwait crude oil containing 2.50 percentsulfur and approximately 30 p.p.m. vanadium were hydrodesulfurized atthe same process conditions, over an alumina-supported catalystrepresentative of the class disclosed herein and another catalystcontaining the same hydrogenating components in the same proportions. Inboth runs the hydrodesulfurization was effected at a hydrogen partialpressure of 1000 p.s.i.g. at a temperature of 790 F. and at a spacevelocity of 2.0 liquid volumes of oil per volume of catalyst per hour,while maintaining a hydrogen to oil ratio of 10,000 s.c.f./bbl. In eachinstance the catalyst was an alumina having deposited thereon 0.5percent nickel, 1 percent cobalt and 8 percent molybdenum. In each casethe catalyst was obtained by impregnation of the calcined alumina basewith aqueous solutions containing the metallic impregnants in solubleform, followed by drying and calcining to the oxide form. The physicalproperties of the respective catalysts, including the pore volumedistribution, is indicated in the following table in which Catalyst A isa catalyst representative of the class disclosed herein and in whichCatalyst B is a catalyst obtained from another commercial alumina base.

Pore Radius, Angstrom Units Catalyst A, Catalyst 13,

Volume, percent Volume, percent 1.3 0. 1 3. 1 0.2 9. 8 0. 4 14. 5 0.3 8.7 0. 2 6. 8 0.2 6. 7 O. 2 6.4 0. 4 6. 5 0. 5 5.2 2.4 5. 5 7. 1 5.0 19.33.8 28.4 4. 9 28. 8 11.9 11.5 0.0 0. 0 0. 47 0. 27 Surface Area, mfl/q221. 2 175. 5 Average Pore Radius, A 91. 7 33.2

tained as bottoms from the vacuum distillation of the atmosphericresidue of a Kuwait crude oil was hydrodesulfurized at equivalentconditions over a catalyst of the class disclosed herein and a similarlyprepared catalyst temperature during startup. Thereafter, in order toinhaving identical hydrogenating components deposited duce acceleratedaging of the catalysts, the same samples thereon but which did not havethe pore volume dison which initial activity with the Kuwait crudecharge tribution of the herein disclosed catalysts. In each instockreferred to above had been deter-mined were then stance the catalyst wasan alumina having deposited therecontacted with a Ceuta crude oil feedstock at 2,000 p.s.i.g. on 0.5% nickel, 1% cobalt and 8% molybdenum. Ineach hydrogen partial pressure, 790 F., and a space velocity 10 case thecatalyst was obtained by impregnation of the of 2 liquid volumes of oilper volume of catalyst per calcined alumina base with aqueous solutionscontaining hour, while maintaining a hydrogen to oil ratio of 10,000 themetallic impregnants in soluble form, followed by s.c.f./bbl. of oil.The Ceuta crude charge stock used for drying and calcining to the oxideform. In these runs aging the catalysts had a gravity of 335 API, asulfur the Catalysts were Pfesulfided y contaflt With a hydrogen"content of 1.10 percent, a nitrogen content of 0.15 perhydrogen sulfidemixture at the reaction conditions. The cent by weight, a carbon residueof 3.39, a vanadium conphy lcal gwpertles of typical samples of therespective tent of 104 p.p.1n., and a nickel content of 13 ppm. Cont ylnchldlng F P Volume qlstnbutwn, are tact of the catalysts with theCeuta crude was continued dlcated the fOHQWmg table, wherein Catalyst 015 a at the o dition i di t d fo 17 d O i to h catalyst representativeof the class disclosed herein and high metals content and highcoke-forming tendencies of 20 111 Catalyst D 15 a catalyfst p p f inequivalent the Ceuta crude, this period of time was equivalent tofashlofl from another Commefclal alumina baseabout 70 days of contactwith the Kuwait crude. After Catalyst C, catalystD, this acceleratedaging period with the Ceuta crude feed Pore Radius, Angstrom Units PoreVol., Poi-e Vol., stock, the catalysts were again contacted with theKuwait percent percent crude charge stock described above, withoutintermediate 300-250 1.2 0.2 regeneration of the catalyst, to determinewhat activity re gggfigg kg 3:? mained in the respective catalysts fordesulfurization of %0 2.8 0.4 the Kuwait crude. Analyses of the agedcatalysts were also 1,83 3; 8% obtained to determine the amount of cokeand vanadium g g deposited thereon. The results of these experiments areF set forth in the following table: 60-50 9.5 32.9 50-40 9.5 27.1Desulfurization, Deposits on Aged -30 8.0 15.5 Catalyst percent by Wt.Catalyst, percent by wt.

% 12.3 Fresh Aged Coke Vanadium 35 04123 0:0 0 Total Pore Vol., mL/g. 0.5128 Catalyst A 79. 2 47. 0 is. s 6.4 Surface Area, /s 165. 0 190. 9Catalyst B 88, 0 24. 0 14. 0 2. 2 Average Pore Radius, 71. 6 53. 2

The hydrodesulfurization conditions employed in the C i z g f gi g gi ggggg g yg% fi iifi 4O comparative runs and the significant productinspections, a ays i y along with the corresponding charge stockinspections, catalysts having a relatively uniform pore volume d1str1-are set fo1tl1 in the following table. bution 1n the range of poreshaving a radius of 0 to 120 Angstrom units, i.e., catalysts of the classdisclosed herein, have poorer initial desulfurization activity forresidual fuel Chara Catalyst Catalyst Stock 0 D oils than conventionalalumina-supported desulfurizanon 45 catalysts having a highconcentration of pores of about opegltmg Cmlditjons:

. ressure, p.s.Lg l, 000 1, 000 the same particular s1ze, 1.e.,catalysts representatlve of Average Tempe flture F 792 791 the typefound useful for desulfurizing distillates. Surgydmgen Rateisicif'lbbl9,284 9,759

un Length, hours 80 80 prisingly, however, it W111 be noted that aftersevere Liquid Hourly SpacoVelooity, aging, Catalyst A retainedsufficient activity still to re- C t move 47 percent of the sulfur fromthe charge stock, l oy 28.39 15.88 whereas Catalyst B had lost so muchactivity through q f mspectlonsI ravity, API 5.5 19.5 17.2 aging that itwas capable of removing only 24 percent of ISqulfur, percent by wt 5.450. 88 1. 24

t 'etb 0.43 0.32 0.30 the sulfur from the charge stock, at the sameconditions. g ggs g g g f Not only is this surpnsing, taking intoconsideratlon the percent by wt 23.11 10.19 11.61 fresh activities ofthe respective catalysts, but also these G%E m 102 icliel, p.p.m 32 8. 413. 6 results are further unexpected in view of the fact that LiquidProgiuctFractions: Gasoline Catalyst A had accumulated markedly greateramounts 5 9 F3 Yleldi Percent by 01. of charge 9. 3 6. 1 of coke andvanadium during the accelerated aging cycle Flllornafli Oifl(}1100670)Yield,percent i 17.9 15.3 than had Catalyst B i f g o 33 As indicatedprevlously, the catalysts of the class dis- Yield,pe1'cent by vol. ofcharge 71.1 77.9 closed herein are also advantageous as compared with igg y, API 13.5 12.3 catalysts normally considered superior forhydrodesul- Viscosity, SUV, sec.: furization of distillates in that theyproduce a total liquid $88., g %22 product of higher API gravity andwhich is lower in v nadiuinj'pfpiifn 5.8 9.6 sulfur, nitrogen, carbonresidue and metals. In addition, Nlckel'pp'm cfltalysts of the disclosedherein Produce S P' From a comparison of the inspections of the productstlally larger quantifies P gasoline t furnace 011 obtained over CatalystC with the corresponding product late, and the desulfurized residueyields are relatively inspections obtained from Catalyst D, it will bSeen that smaller, of higher quality and of markedly lower viscosity. inthe case of the run carried out with Catalyst C, a The latter feature isimportant since lower viscosity residcatalyst representative of theclass disclosed herein, the ual oils require smaller proportions ofcutter oil to render total liquid product had a higher API gravity andwas them useful as residual fuels. lower in sulfur, nitrogen, carbonresidue and metals than The advantages indicated above have beendemonstrated the product obtained in the run in which Catalyst D, a bycomparative experiments in which a residual oil obcatalystrepresentative of the class of catalysts known to be useful forhydrosulfurization of distillates is utilized. In addition, it will beseen that the total liquid product obtained with Catalyst C containedrelatively larger proportions of gasoline and furnace oil, andcorrespondingly lower yields of residue. Finally, the residue producedwith Catalyst C is of higher quality than that produced with Catalyst D.All of these results are the more surprising in view of the fact thatCatalyst C at the end of the run had accumulated a markedly greatercarbon content than had Catalyst D.

\Ve claim:

1. A process for catalytically hydrodesulfurizing a sulfur-containingpetroleum oil that contains residual components and metalliccontaminants normally capable of acting as catalyst poisons, comprisingcontacting said oil with hydrogen at hydrodesulfurization conditions inthe presence of a catalyst comprising a hydrogenating componentcomposited with an alumina base, said composite catalyst having not morethan 15 percent of the volume of the pores having a radius in the rangeof to 300 Angstrom units in any Angstrom unit increment, starting at 0Angstrom units, of pore radius in the range of pores having a 0 to 120Angstrom unit radius, and a'so having at least about 10 percent of suchpore volume in pores having a radius of less than 30 Angstrom units, atleast percent of such pore volume in pores having a radius greater thanAngstrom units and less than 70 Angstrom units, and at least 30 percentof such pore volume in pores having a radius of greater than 70 Angstromunits and less than 120 Angstrom units.

2. A process for catalytically hydrodesulfurizing a sulfur-containingpetroleum oil'that contains residual components and metalliccontaminants that are normally capable of acting as catalyst poisons,comprising contacting said oil with hydrogen at a partial pressure inthe range of about 500 to 4000 p.s.i.g., at a temperature, afterstartup, in the range of about 600 to 850 F, at a space velocity in therange of about 0.1 to 10 volumes of liquid per volume of catalyst perhour, while maintaining a hydrogenzoil ratio in the range of about 1000to 15,000 s.c.f./bbl. oil, in the presence of a catalyst comprising ahydrogenating component composited with an alumina base, said compositecatalyst having not more than 15 percent of the volume of the poreshaving a radius in the range of 0 to 300 Angstrom units in any 10'Angstrom unit increment, starting at 0 Angstrom units, of pore radius inthe range of pores having a 0 to 120 Angstrom unit radius, and alsohaving at least about 10 percent of such pore volume in pores having aradius of less than 30 Angstrom units, at least 15 percent of such porevolume in pores having a radius greater than 30 Angstrom units and lessthan 70 Angstrom units, and at least 30 percent of such pore volume inpores having a radius of greater than 70 Angstrom units and less than120 Angstrom units.

3. The process of claim 2 wherein the hydrogen partial pressure is inthe range of about 1000 to 2000 p.s.i.g., the temperature, afterstartup, is in the range of about 650 to 800 F., the space velocity isin the range of about 0.5 to 5 volumes of liquid per volume of catalystper hour, and the hydrogenzoil ratio is in the range of about 4000 to10,000 s.c.f./bbl. oil.

4. The process of claim 2 wherein the catalyst also has a surface areaof at least 100 square meters per gram.

5. The process of claim 2 wherein the hydrogenating component of thecatalyst is at least one member of the group consisting of metals ofGroup VI-B and Group VIII in a form capable of promoting hydrogenationreactions.

6. The process of claim 5 wherein the hydrogenating component isselected from the group consisting of sulfides and oxides of (a) acombination of about 2 to 25 percent by weight molybdenum and at leasttwo iron group metals where the iron group metals are present in suchproportions that the atomic ratio of each iron group metal with respectto molybdenum is less than about 0.4, and (b) a combination of about 5to 40 percent by weight of nickel and tungsten where the atomic ratio oftungstenznickel is about 110.1 to 5.

7. The process of claim 6 wherein the hydrogenating component isselected from the group consisting of sultides and oxides of (a) acombination of about 4 to 16 percent by weight molybdenum and at leasttwo iron group metals, where the iron group metals are present in suchproportions that the atomic ratio of each iron group metal with respectto molybdenum is less than about 0.4, and (b) a combination of about 10to 25 percent by weight of nickel and tungsten where the atomic ratio oftungstenmickel is about 1:03 to 4.

8. A process for catalytically hydrodesulfurizing a sulfurcontainingpetroleum oil that contains residual components and metalliccontaminants that are normally capable of acting as catalyst poisons,comprising contacting said oil with hydrogen at a hydrogen partialpressure in the range of about 1000 to 2000 p.s.i.g. at a temperature,after startup, in the range of about 650 to 800 F., at a space velocityin the range of about 0.5 to 5 volumes of liquid per volume of catalystper hour, while maintaining a hydrogenzoil ratio in the range of about1000 to 15,000 s.c.f./bbl. oil, in the presence of a catalyst comprisinga hydrogenating component composited with an alumina base, saidcomposite catalyst having not more than 15 percent of the volume of thepores having a radius in the range of O to 300 Angstrom units in any 10Angstrom unit increment, starting at 0 Angstrom units, of pore radius inthe range of pores having a 0 to Angstrom unit radius, and also havingat least about 10 percent of such pore volume in pores having a radiusof less than 30 Angstrom units, at least 15 percent of such pore volumein pores having a radius greater than 30 Angstrom units and less than 70Angstrom units, and at least 30 percent of such pore volume in poreshaving a radius of greater than 70 Angstrom units and less than 120Angstrom units, and where the hydrogenating component is selected fromthe group consisting of sulfides and oxides of (a) a combination ofabout 4 to 16 percent by weight molybdenum and at least two iron groupmetals, where the iron group metals are present in such proportions thatthe atomic ratio of each iron group metal with respect to molybdenum isless than about 0.4, and (b) a combination of about 10 to 25 percent byweight of nickel and tungsten where the atomic ratio of tungsten tonickel is about 1:03 to 4, the reaction temperature and the spacevelocity being so controlled as to efiect hydrogen consumption in therange of about 1 to 5 gram mols of hydrogen per gram atomic weight ofsulfur removed from said oil.

References Cited UNITED STATES PATENTS 3,264,062 8/1966 Kehl et al252463 3,297,588 1/1967 Kehl et a1 252-465 3,322,666 5/1967 Beuther etal 208-216 3,340,180 9/1967 Beuther et al. 208-216 SAMUEL P. JONES,Primary Examiner.

